The use of dihalobenzene disulfone compounds to make poly(aryl ether sulfones) generally is known to the art. See U.S. Pat. Nos. 3,647,751 to Darsow; 3,960,815 to Darsow et al.; 4,009,149 to King et al.; 4,056,511 to Staniland; and 4,105,635 to Freeman, for example. These patents generally disclose making poly(aryl ether sulfones) wherein some of the polymers disclosed therein are made using compounds of the Formula ##STR3## wherein X is halogen and Q is a divalent benzenoid moiety such as phenylene, biphenylene, biphenylene ether, terphenylene, and the like.
The Friedel Crafts catalyzed synthesis of dihalobenzene disulfone compounds themselves has been variously described in the patent and technical journal literature. U.S. Pat. No. 4,303,776 to Baron et al. discloses the ferric chloride synthesis of 4,4'-bis(4-chlorophenyl sulfonyl) biphenyl from biphenyl and 4-chlorobenzene sulfonyl chloride (pCBSC) wherein the pCBSC apparently is used as both a reactant and a solvent. The patent states that a 45% conversion was obtained after purification. Cornell et al., Soc. Plas. Eng. Tech. Papers, 21, 621-623 (1975) disclose virtually the same synthesis on a laboratory scale and report scaled up large reactor yields in excess of 80% when the reaction is run in nitrobenzene (a conventional solvent for Friedel-Crafts reactions) and a temperature schedule gradually increasing from 70.degree. C. to 130.degree. C. is employed. The use of nitrobenzene as a solvent is commercially unattractive, however, due to its high toxicity, a Permissible Exposure Limit of only 1 part per million being allowed in the workplace (NIOSH/OSHA Pocket Guide To Chemical Hazards, Govt. Printing Office, September, 1978).
Mixed solvent systems have been disclosed for use with some Friedel-Crafts polymerization systems. International application number PCT/US84/00465 (Raychem Corporation), published Oct. 11, 1984 under publication number WO 84/03891 discloses an improved electrophilic synthesis of poly(arylene ketones) in a reaction medium comprising a Lewis acid (i.e., a Friedel-Crafts catalyst), a Lewis base, and a non-protic diluent. A large number of Lewis bases are disclosed, including nitro compounds of which nitropropane and nitrobenzene are specifically cited. Diluents mentioned include methylene chloride and dichloroethane. The applicant states that the Lewis acid complexes with the Lewis base, and that the complex appears to act as a solvent for the polymer-Lewis acid complex formed during the reaction thereby maintaining the polymer in solution or in a reactive gel state. The applicant states that the reaction mixture is more tractable to work up and believes that the solubilization of the polymer by the Lewis acid/Lewis base complex aids in achieving high molecular weight.
A. Fritz, in Poly. Prepr., Am. Chem. Soc., Div. Polym. Chem., 12(1), 232-239, (March 1971), discloses that the Friedel-Crafts condensation of aromatic isopropylchlorides with aromatic compounds can be adapted to polymer formation. The article states that it was necessary to solvate the Lewis acids with nitro compounds such as nitrobenzene or nitroalkanes in order to yield high molecular weight products. It was also stated to be essential to use metathetic catalysts in order to prevent reversibility and indane formation. Solvents disclosed included chloromethane, methylene chloride, chlorobenzene, dichlorobenzene, and dichloroethane.
Mixed solvent systems have also been disclosed in the patent literature in reaction systems which are far removed from those of the above publications. Thus U.S. Pat. No. 4,053,517 to Reininger et al., for example, discloses the Friedel-Crafts acylation of phloroglucinol wherein the acylation is conducted in a solvent system composed of nitromethane and methylene chloride.